40 CFR 61.03: Units and abbreviations.

Used in this part are abbreviations and symbols of units of measure. These are defined as follows:

(a) System International (SI) units of measure:

A = ampere

g = gram

Hz = hertz

J = joule

K = degree Kelvin

kg = kilogram

m = meter

m 2 = square meter

m 3 = cubic meter

mg = milligram = 10−3gram

mm = millimeter = 10−3meter

Mg = megagram = 10 6gram

mol = mole

N = newton

ng = nanogram = 10−9gram

nm = nanometer = 10−9meter

Pa = pascal

s = second

V = volt

W = watt

Ω = ohm

µg = microgram = 10−6gram

(b) Other units of measure:

°C = degree Celsius (centigrade)

cfm = cubic feet per minute

cc = cubic centimeter

Ci = curie

d = day

°F = degree Fahrenheit

ft 2 = square feet

ft 3 = cubic feet

gal = gallon

in = inch

in Hg = inches of mercury

in H2O = inches of water

l = liter

lb = pound

lpm = liter per minute

min = minute

ml = milliliter = 10−3liter

mrem = millirem = 10−3 rem

oz = ounces

pCi = picocurie = 10−12 curie

psig = pounds per square inch gage

°R = degree Rankine

µl = microliter = 10−6liter

v/v = volume per volume

yd 2 = square yards

yr = year

(c) Chemical nomenclature:

Be = beryllium

Hg = mercury

H2O = water

(d) Miscellaneous:

act = actual

avg = average

I.D. = inside diameter

M = molar

N = normal

O.D. = outside diameter

% = percent

std = standard